Separate display item clients for negative and normal/positive z-order children

third_party/WebKit/Source/platform/graphics/paint/PaintController.cpp

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "config.h"
 #include "platform/graphics/paint/PaintController.h"
 
 #include "platform/NotImplemented.h"
 #include "platform/TraceEvent.h"
 #include "platform/graphics/GraphicsLayer.h"
@@ skipping 48 matching lines @@
     ASSERT(!m_constructionDisabled);
     ASSERT(!skippingCache() || !displayItem.isCached());
 
     if (displayItem.isCached())
         ++m_numCachedItems;
 
 #if ENABLE(ASSERT)
     // Verify noop begin/end pairs have been removed.
     if (m_newDisplayItemList.size() >= 2 && displayItem.isEnd()) {
         const auto& beginDisplayItem = m_newDisplayItemList[m_newDisplayItemList.size() - 2];
-        if (beginDisplayItem.isBegin() && !beginDisplayItem.isSubsequence() && !beginDisplayItem.drawsContent())
+        if (beginDisplayItem.isBegin() && beginDisplayItem.type() != DisplayItem::Subsequence && !beginDisplayItem.drawsContent())
             ASSERT(!displayItem.isEndAndPairedWith(beginDisplayItem.type()));
     }
 #endif
 
     if (!m_scopeStack.isEmpty())
         displayItem.setScope(m_scopeStack.last());
 
 #if ENABLE(ASSERT)
     size_t index = findMatchingItemFromIndex(displayItem.nonCachedId(), m_newDisplayItemIndicesByClient, m_newDisplayItemList);
     if (index != kNotFound) {
@@ skipping 159 matching lines @@
                 return context.nextItemToIndex++;
 
             addItemToIndexIfNeeded(item, context.nextItemToIndex - m_currentPaintArtifact.displayItemList().begin(), context.displayItemIndicesByClient);
         }
     }
     return currentEnd;
 }
 
 void PaintController::copyCachedSubsequence(DisplayItemList::iterator& currentIt, DisplayItemList& updatedList)
 {
-    ASSERT(currentIt->isSubsequence());
+    ASSERT(currentIt->type() == DisplayItem::Subsequence);
     ASSERT(!currentIt->scope());
-    DisplayItem::Id endSubsequenceId(currentIt->client(), DisplayItem::subsequenceTypeToEndSubsequenceType(currentIt->type()), 0);
+    DisplayItem::Id endSubsequenceId(currentIt->client(), DisplayItem::EndSubsequence, 0);
     do {
         // We should always find the EndSubsequence display item.
         ASSERT(currentIt != m_currentPaintArtifact.displayItemList().end());
         ASSERT(currentIt->isValid());
         updatedList.appendByMoving(*currentIt);
         ++currentIt;
     } while (!endSubsequenceId.matches(updatedList.last()));
 }
 
 // Update the existing display items by removing invalidated entries, updating
@@ skipping 93 matching lines @@
 #if ENABLE(ASSERT)
             if (RuntimeEnabledFeatures::slimmingPaintUnderInvalidationCheckingEnabled()) {
                 DisplayItemList::iterator temp = currentIt;
                 checkUnderInvalidation(newIt, temp);
             }
 #endif
             if (newDisplayItem.isCachedDrawing()) {
                 updatedList.appendByMoving(*currentIt);
                 ++currentIt;
             } else {
-                ASSERT(newDisplayItem.isCachedSubsequence());
+                ASSERT(newDisplayItem.type() == DisplayItem::CachedSubsequence);
                 copyCachedSubsequence(currentIt, updatedList);
-                ASSERT(updatedList.last().isEndSubsequence());
+                ASSERT(updatedList.last().type() == DisplayItem::EndSubsequence);
             }
         } else {
             ASSERT(!newDisplayItem.isDrawing()
                 || newDisplayItem.skippedCache()
                 || !clientCacheIsValid(newDisplayItem.client())
                 || (RuntimeEnabledFeatures::slimmingPaintOffsetCachingEnabled() && paintOffsetWasInvalidated(newDisplayItem.client())));
 
             updatedList.appendByMoving(*newIt);
 
             if (isSynchronized)
@@ skipping 73 matching lines @@
     // When under-invalidation-checking is enabled, the forced painting is following the cached display item.
     DisplayItem::Type nextItemType = DisplayItem::nonCachedType(newIt->type());
     ++newIt;
     ASSERT(newIt->type() == nextItemType);
 
     if (newIt->isDrawing()) {
         checkCachedDisplayItemIsUnchanged("", *newIt, *currentIt);
         return;
     }
 
-    ASSERT(newIt->isSubsequence());
+    ASSERT(newIt->type() == DisplayItem::Subsequence);
 
 #ifndef NDEBUG
     CString messagePrefix = String::format("(In CachedSubsequence of %s)", newIt->clientDebugString().utf8().data()).utf8();
 #else
     CString messagePrefix = "(In CachedSubsequence)";
 #endif
 
-    DisplayItem::Id endSubsequenceId(newIt->client(), DisplayItem::subsequenceTypeToEndSubsequenceType(newIt->type()), 0);
+    DisplayItem::Id endSubsequenceId(newIt->client(), DisplayItem::EndSubsequence, 0);
     while (true) {
         ASSERT(newIt != m_newDisplayItemList.end());
         if (newIt->isCached())
             checkUnderInvalidation(newIt, currentIt);
         else
             checkCachedDisplayItemIsUnchanged(messagePrefix.data(), *newIt, *currentIt);
 
         if (endSubsequenceId.matches(*newIt))
             break;
 
@@ skipping 84 matching lines @@
 
 void PaintController::showDebugData() const
 {
     WTFLogAlways("current display item list: [%s]\n", displayItemListAsDebugString(m_currentPaintArtifact.displayItemList()).utf8().data());
     WTFLogAlways("new display item list: [%s]\n", displayItemListAsDebugString(m_newDisplayItemList).utf8().data());
 }
 
 #endif // ifndef NDEBUG
 
 } // namespace blink